Palladium-Catalyzed Cocyclotrimerization of Allenes with Arynes: Selective Synthesis of Phenanthrenes
作者:Yi-Lin Liu、Yun Liang、Shao-Feng Pi、Xiao-Cheng Huang、Jin-Heng Li
DOI:10.1021/jo900117c
日期:2009.4.17
Palladium-catalyzed cocyclotrimerization of allenes with arynes has been developed for selectively synthesizing phenanthrenes. In the presence of [(allyl)PdCl]2 and P(o-tol)3, a variety of allenes, including internal and terminal allenes, underwent the cocyclotrimerization with arynes to afford the corresponding phenanthrenes in moderate to good yields. The results showed the selectivity of the reaction
DBU-Catalyzed Diastereo/Regioselective Access to Highly Substituted Spiro-oxetane Oxindoles <i>via</i> Ring Annulation of Isatins and Allenoates
作者:Basavaraja Durugappa、Athira C S、Siddalingeshwar V. Doddamani、Sasidhar B. Somappa
DOI:10.1021/acs.joc.3c00664
日期:2023.7.7
A facile and efficient method for the diastereo/regioselectivesynthesis of highly functionalized spiro-oxetane oxindoles has been described. The 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-catalyzed reaction proceeds via spiro-annulation of isatins and allenoates. The reaction is compatible with a wide range of isatins containing electron-donating groups (EDGs) and electron-withdrawing groups (EWGs)
3]-sigmatropic rearrangement involving stabilized sulfur ylides and allenoates has been thoroughly established. The scope and utility of this reaction have been extensively studied resulting in C–C bond formation under mild conditions with greater than 20 examples reported. A highlight of the work is the simple and fully operational process that does not involve the use of carbenes or the associated hazardous